How to troubleshoot slow InfoPath form performance

InfopathToday I needed to solve some performance issues regarding a slow loading InfoPath form. The form was build on a SharePoint list that contained a lot of items (>5000) and 10 lookup columns. The form was loading real slow. I mean really slow. It took more than 6 minutes to display the form.

I started troubleshooting by using Bing and came on these pages:

None of these articles really helped solving my problem. So I tried this:

  • The lookups where also linked to large lists, I archived the items in the lists (exported some items to Excel or stored them in an archive list)
  • I ended with removing the InfoPath form and used the default SharePoint forms again with some help of the SPServices magic Javascript library.

The form is still slow but now it takes only 100 seconds to load. This is somewhat acceptable for the users.